Continuous oil pipe operation apparatuses are widely applied in different tasks in oil and gas field exploration and development. In recent years, as the usage and applied range of injection heads of continuous oil pipes were extended continuously, the operability and maintainability of injection heads of continuous oil pipes have become more and more important. A holding device for injector head of continuous oil pipe is a key component for continuous oil pipe operation apparatuses, in which the sprocket is driven by a hydraulic motor that can rotate in normal direction/reversed direction, and the continuous oil pipe is clamped by the clamping assembly between the chain links, so that the continuous oil pipe moves with the chain; thus, the continuous oil pipe can enter into and exit from the shaft.
At present, clamping devices that employ an integral pushing plate are a sort of commonly used injector head clamping devices, and have the following basic structure: the saddle-shaped clamping block is mounted on the chain, an integral pushing plate fixed to the supporting plate is arranged at inner side of the two chains respectively, and a plurality of wheel bearings are mounted on the integral pushing plate. The pushing plate is pushed by the hydraulic oil cylinders fixed to the supporting plate together, so that the wheel bearings on the integral pushing plate press the saddle-shaped clamping block and thereby clamp the continuous oil pipe. The structure described above have the following drawbacks in actual application: the pushing plate with bearings has poor maintainability, and is difficult to replace or repair; in addition, the clamping block seat that slides on the bearings may be worn easily and is difficult to replace; moreover, since the pushing plate is not fixed flexibly on the supporting plate, the pushing plate may be offset and seized, and therefore the clamping block is not stressed evenly and may be worn severely, causing damages to the oil pipe or machine; furthermore, since the pushing plate carries bearing bracket and bearings, the clamping device in such a structure is large in size, and even the clamping oil cylinders have to be mounted outside of the chain ring; consequently, the flexibility of the injector head is compromised.